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Applying circuit theory and landscape linkage maps to reintroduction planning for California condors

December 31, 2019

Conservation practitioners are increasingly looking to species translocations as a tool to recover imperiled taxa. Quantitative predictions of where animals are likely to move when released into new areas would allow managers to better address the social, institutional, and ecological dimensions of conservation translocations. Using >5 million California condor (Gymnogyps californianus) occurrence locations from 75 individuals, we developed and tested circuit-based models to predict condor movement away from release sites. We found that circuit-based models of electrical current were well calibrated to the distribution of condor movement data in southern and central California (continuous Boyce Index = 0.86 and 0.98, respectively). Model calibration was improved in southern California when additional nodes were added to the circuit to account for nesting and feeding areas, where condor movement densities were higher (continuous Boyce Index = 0.95). Circuit-based projections of electrical current around a proposed release site in northern California comported with the condor’s historical distribution and revealed that, initially, condor movements would likely be most concentrated in northwestern California and southwest Oregon. Landscape linkage maps, which incorporate information on landscape resistance, complement circuit-based models and aid in the identification of specific avenues for population connectivity or areas where movement between populations may be constrained. We found landscape linkages in the Coast Range and the Sierra Nevada provided the most connectivity to a proposed reintroduction site in northern California. Our methods are applicable to conservation translocations for other species and are flexible, allowing researchers to develop multiple competing hypotheses when there are uncertainties about landscape or social attractants, or uncertainties in the landscape conductance surface.

Publication Year 2019
Title Applying circuit theory and landscape linkage maps to reintroduction planning for California condors
DOI 10.1371/journal.pone.0226491
Authors Jesse D'Elia, Joe Brandt, LJ Burnett, Susan M. Haig, Jeffrey P Hollenbeck, S Kirkland, B G Marcot, A Punzalan, C J West, T Williams-Claussen, Rachel Wolstenholme, Richard Young
Publication Type Article
Publication Subtype Journal Article
Series Title PLoS ONE
Index ID 70215873
Record Source USGS Publications Warehouse
USGS Organization Forest and Rangeland Ecosystem Science Center